Ferroelectric Behavior in Polyamides of m-Xylylenediamine and Dicarboxylic Acids

Abstract

We study the level spacing distribution p(s) in the spectrum of random networks. According to our numerical results, the shape of p(s) in the Erdős-Rényi (E-R) random graph is determined by the average degree k and p(s) undergoes a dramatic change when k is varied around the critical point of the percolation transition, k = 1. When k 1, the p(s) is described by the statistics of the Gaussian orthogonal ensemble (GOE), one of the major statistical ensembles in Random Matrix Theory, whereas at k = 1 it follows the Poisson level spacing distribution. Closely above the critical point, p(s) can be described in terms of an intermediate distribution between Poisson and the GOE, the Brodydistribution. Furthermore, below the critical point p(s) can be given with the help of the regularized Gamma-function. Motivated by these results, we analyse the behaviour of p(s) in real networks such as the internet, a word association network and a protein-protein interaction network as well. When the giant component of these networks is destroyed in a node deletion process simulating the networks subjected to intentional attack, their level spacing distribution undergoes a similar transition to that of the E-R graph.

Ferroelectric behavior and polarization mechanism in odd‐odd polyamide 11,11

“…Recent research has shown that even‐odd polyamide 6,9 exhibit D‐E loops, although the ferroelectric activity is low . The ferroelectric hysteresis loop is also observed in quenched polyamide MXDn, and the nature of the ferroelectricity has been attributed to the amide groups in amorphous regions . Other polyamides such as polyamide 6I, 6T, 6I/6T copolymer, and BACn all exhibit ferroelectric behavior and clear D‐E hysteresis loops are obtained …”

“…19 The ferroelectric hysteresis loop is also observed in quenched polyamide MXDn, and the nature of the ferroelectricity has been attributed to the amide groups in amorphous regions. 20 Other polyamides such as polyamide 6I, 6T, 6I/6T copolymer, and BACn all exhibit ferroelectric behavior and clear D-E hysteresis loops are obtained. 21,22 However, there are few reports in the literature about piezoelectricity and ferroelectricity in odd-odd polyamides.…”

Ambipolar organic field-effect transistor using gate insulator hysteresis

“…This type of slow relaxation phenomenon has also been observed in the ferrodielectric polymer polyvinylidene fluoride. 15,16 While the hysteresis is not yet fully understood, by applying a voltage larger than the coercive voltage to the gate insulator in an effort to facilitate poling, we found that a large amount of charge ͑Q͒, which obeys Q = P r + CV, had accumulated at the interface.…”

Why ferroelectric polyvinylidene fluoride is special

“…The odd nylons [53][54][55][56][57][58], which have all the carbonyl groups on the same side of the molecule, are indeed ferroelectric, with polarizations increasing with carbonyl content, ranging from 40 mC/m 2 to 130 mC/m 2 [56], which is comparable to the range for PVDF and its copolymers. The odd nylons are inexpensive and easy to process and make good piezoelectric [53][54][55] and pyroelectric [53,57,59] materials. Polarization switching, however, is hindered by hydrogen bonding between the =O and CH 2 on neighboring chains, making these materials difficult to polarize or switch.…”